Dual-walled or coaxial pipe systems are used to convey fluid from one location to another. Dual-walled pipes include an inner pipe disposed within and an outer pipe. In one example, fluid may be conveyed through the inner pipe while the outer pipe contains any fluid that escapes from the inner pipe. While dual-walled pipe systems may be used to convey many types of fluid, they are particularly useful for conveying fuels, hazardous liquids, toxic gases, etc. Dual-walled pipes are available in a variety of different sizes, and may convey two fluids, such as a first fluid through the inner pipe and a second fluid through the annulus between the inner and outer pipes.
When used as a natural gas supply line, dual-walled pipe systems may prevent leakage of natural gas into the atmosphere in case of damage to the inner pipe, a seal, or a weld. The outer pipe may contain the gas leaking from the inner pipe. However, the inner and outer pipes may be connected to various end fittings or flanges that connect the inner and outer pipes to a crankcase or other device.
In dual-walled pipe systems, it may be desirable to provide access points to the primary passage inside the inner pipe for sensors or other components. Typical sensors may include temperature, pressure, or other types of sensors used to provide feedback regarding one or more parameters of the fluid. The insertion of sensors through the outer and inner pipes, however, creates a potential fluid leakage path. As such, sensors or other components requiring direct access to the primary passage must often be located within containment rooms or structures. The need for such containment not only increases costs but limits the proximity at which the sensors may be placed relative to other system components, such as an engine. Accordingly, it would be advantageous to provide access to the primary passage for insertion of sensors or other components while still containing leaked fluid without requiring bulky or additional containment structures.